<?php
function my_queryable_custom_fields() {
	register_queryable_custom_field( 'price', array(
		'numeric' => true
	) );
		register_queryable_custom_field( 'wpbl_availablity', array(
		'numeric' => false
	) );
		register_queryable_custom_field( 'wpbl_user', array(
		'numeric' => false
	) );
		register_queryable_custom_field( 'bookid', array(
		'numeric' => true
	) );
		register_queryable_custom_field( 'received_date', array(
		'numeric' => true
	) );
		register_queryable_custom_field( 'pub_year', array(
		'numeric' => true
	) );
}
add_action('init', 'my_queryable_custom_fields');

?>